/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.pulsar.functions.api;

import java.util.Collection;
import org.apache.pulsar.common.classification.InterfaceAudience;
import org.apache.pulsar.common.classification.InterfaceStability;

/**
 * This is the interface of the windowed function api. The process method is called
 * for every triggered window.
 */
@InterfaceAudience.Public
@InterfaceStability.Stable
@FunctionalInterface
public interface WindowFunction<I, O> {
    /**
     * Process the input.
     *
     * @return the output
     */
    O process(Collection<Record<I>> input, WindowContext context) throws Exception;
}